How can I make a hexa grid follow a curvy shape without it being deformed?
I think you can get something rather good with this method:


First here is a close-up shot of your radio.





Create a mesh > Geodesic Dome with these parameters (or similar):





Select all, bevel the vertices with shiftctrlB. Then delete Only Faces.





Keep only 1/8th of the ball, you have your corner. Enable the Snap (Vertex mode) and the Merge Vertices options. Begin to duplicate the borders to make the flat surface.





At the end give it a Subdivision Surface and a Solidify modifier. Maybe a Shrinkwrap if you want to correct the shape a bit.